Grails/GORM: No signature of method is is applicable for argument types

Question

I'm trying to put together a basic blog application using Grails 2.4.4. My domain model is as follows:

class Commentable {
  String title
  static hasMany = [comments:Comment]   
}

class Comment extends Commentable {
  static belongsTo = [target:Commentable]
}

class Post extends Commentable {
  static hasMany = [tags:Tag]
}

class Tag {
  String label
  static hasMany = [posts:Post]
  static belongsTo = Post
}

In the init method of BootStrap.groovy, I'm trying to create a Post and a Tag as follows

def post = new Post();
post.setTitle("Post1");
post.save();

def tag = new Tag();
tag.setLabel("Tag1");
tag.save();

tag.addToPost(post);
tag.save();

which produces the error message below:

Message: No signature of method: io.dimitris.blog.Tag.addToPost() is 
applicable for argument types: (io.dimitris.blog.Post) values: 
[io.dimitris.blog.Commentable : 1]
Possible solutions: addToPosts(java.lang.Object)

Any hints on what I'm doing wrong would be really appreciated.

Answer 1

You are calling tag.addToPost(post) but you need tag.addToPosts(post). The hasMany property is static hasMany = [posts:Post]. The key in that map dictates the method name. If you change that to static hasMany = [post:Post] then the method would be addToPost(post), but the name would make less sense.